A lacunar infarction (LACI) can cause damage to the surrounding brain tissue and place an individual at greater risk for future major stroke. LACI is associated with hypertension and hypertension is associated with left atrial enlargement. It is important to identify a high-risk patient who is more vulnerable to suffering a LACI in hypertensive group. So, we studied whether left atrium size is an independent risk predictor for LACI in hypertensive patients. We performed cross-sectional analysis of 365 patients with hypertension at Shanghai Ninth People’s Hospital from January 2016 to January 2017. The results showed that left atrial diameter(LAD), left atrial volume (LAV) and the ratio of left atrial diameter to left ventricular diameter (LAD/LVD) were significantly associated with LACI in hypertensive patients. Based on the ROC curve analysis, the area under the ROC curve (AUC) of LAV used to predict LACI was 0.737 (95% CI: 0.686 – 0.788), and the AUC of LAD/LVD was 0.784 (95% CI: 0.737 – 0.830). The optimal cut-off value for LAV was 30.14, and the sensitivity and specificity were 72% and 63%, respectively. The optimal cut-off value for LAD/LVD was 0.757, and the sensitivity and specificity were 77% and 70%, respectively. LAV or LAD/LVD played an important role in LACI with hypertension and could be an independent risk factor in hypertensive patients.